std:: owner_equal
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Defined in header
<memory>
|
||
|
struct
owner_equal
;
|
(since C++26) | |
This function object provides owner-based (as opposed to value-based) mixed-type equal comparison of both
std::weak_ptr
and
std::shared_ptr
. The comparison is such that two smart pointers compare equivalent only if they are both empty or if they share ownership, even if the values of the raw pointers obtained by
get()
are different (e.g. because they point at different subobjects within the same object).
std::owner_equal
deduces the parameter types from the arguments.
Nested types
| Nested type | Definition |
is_transparent
|
unspecified |
Member functions
|
operator()
|
compares its arguments using owner-based semantics
(function) |
std::owner_equal:: operator()
|
template
<
class
T,
class
U
>
bool
operator
(
)
(
const
std::
shared_ptr
<
T
>
&
lhs,
|
(since C++26) | |
|
template
<
class
T,
class
U
>
bool
operator
(
)
(
const
std::
shared_ptr
<
T
>
&
lhs,
|
(since C++26) | |
|
template
<
class
T,
class
U
>
bool
operator
(
)
(
const
std::
weak_ptr
<
T
>
&
lhs,
|
(since C++26) | |
|
template
<
class
T,
class
U
>
bool
operator
(
)
(
const
std::
weak_ptr
<
T
>
&
lhs,
|
(since C++26) | |
Compares lhs and rhs using owner-based semantics. Effectively calls lhs. owner_equal ( rhs ) .
The equal comparison is an equivalence relation.
lhs and rhs are equivalent only if they are both empty or share ownership.
Parameters
| lhs, rhs | - | shared-ownership pointers to compare |
Return value
true if lhs and rhs are both empty or share ownership as determined by the owner-based equal comparison, false otherwise.
Notes
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_smart_ptr_owner_equality
|
202306L | (C++26) |
Enabling the use of
std::shared_ptr
and
std::weak_ptr
as keys in
unordered associative containers
|
See also
|
(C++26)
|
provides owner-based equal comparison of shared pointers
(public member function of
std::shared_ptr<T>
)
|
|
(C++26)
|
provides owner-based equal comparison of weak pointers
(public member function of
std::weak_ptr<T>
)
|